Electric hand tool

Abstract

A power hand tool including a manually engageable housing, a prime mover within the housing, a tool bit engaging chuck projecting from the housing, power transmission means within the housing and between the prime mover and the chuck; said power transmission is operable to selectively drive the chuck rotatively or reciprocally. The chuck is driven rotatively by a tube driven by the transmission and coupled with the chuck for free relative axial movement and for relative circumferential drive; the chuck is driven reciprocally by an eccentric drive means connected with the transmission and coupled with the chuck for free relative rotation and for reciprocal axial drive.

Having described my invention, I claim: 
     
       1. A power tool comprising an elongate manually engageable housing with front and rear ends and defining a longitudinal axis of the tool, an elongate axially extending rotary drive tube rotatably supported by the housing and having a rear end portion accessible from within the housing and a forward portion projecting forwardly from the housing, an elongate chuck with a rear portion projecting into the tube and a forward tool bit engaging portion projecting forwardly from the tube, rotary coupling means between the tube and the chuck establishing rotary driving engagement therebetween, an axially shiftable drive member rearward of the chuck, axial coupling means between the chuck and the member establishing axial driving engagement therebetween, said axial driving engagement being substantially free of lost motion between said drive member and said chuck, a prime mover in the housing, a power transmission connected with the prime mover and including an eccentric drive means connected with said member and a rotary driven element connected with the tube. 
     
     
       2. The tool set forth in claim 1 wherein said rotary coupling means includes axially extending radially outwardly opening grooves in the chuck and radially inwardly projecting drive parts on the tube and engaged in the grooves. 
     
     
       3. The tool set forth in claim 2 wherein the axial coupling means includes an elongate axially extending female section with a cavity defining forwardly and rearwardly disposed drive surfaces and an elongate axially extending male section with a drive head with forwardly and rearwardly disposed drive faces rotatably engaged in the cavity and means connecting one of said sections with the chuck and the other section with said member. 
     
     
       4. The tool set forth in claim 1 wherein the axial coupling means includes an elongate axially extending female section with a cavity defining forwardly and rearwardly disposed drive surfaces and an elongate axially extending male section with a drive head with forwardly and rearwardly disposed drive faces rotatably engaged in the cavity and means connecting one of said sections with the chuck and the other section with said member. 
     
     
       5. The tool set forth in claim 1 wherein said prime mover has a rotary drive shaft, said power transmission including a first gear train connected with and between the drive shaft and the tube, one gear of said first gear train being shiftable into and out of driving engagement with a related gear in that gear train, a second gear train connected with and between the drive shaft and said eccentric drive means, one gear of said second gear train being shiftable into and out of driving engagement with a related gear in that gear train and manually operable means coupled with the shiftable gears of the first and second gear trains to shift those gears whereby driving engagement of those gears with related gears can be selectively made and broken. 
     
     
       6. The tool set forth in claim 5 wherein said rotary coupling means includes axially extending radially outwardly opening grooves in the chuck and radially inwardly projecting drive parts on the tube and engaged in the grooves. 
     
     
       7. The tool set forth in claim 6 wherein the axial coupling means includes an elongate axially extending female section with a cavity defining forwardly and rearwardly disposed drive surfaces and an elongate axially extending male section with a drive head with forwardly and rearwardly disposed drive faces rotatably engaged in the cavity and means connecting one of said sections with the chuck and the other section with said member. 
     
     
       8. The tool set forth in claim 5 wherein the axial coupling means includes an elongate axially extending female section with a cavity defining forwardly and rearwardly disposed drive surfaces and an elongate axially extending male section with a drive head with forwardly and rearwardly disposed drive faces rotatably engaged in the cavity and means connecting one of said sections with the chuck and the other section with said member. 
     
     
       9. The tool set forth in claim 8 wherein the eccentric drive means includes a drive arm carried by a sleeve and pivotally connected with the drive member and a rotary part with the sleeve rotatably supported on an eccentric axis; the first gear train includes a first drive gear on the drive shaft and a first driven gear connected with the rotary part concentric with the rotary axis and engageable with the first drive gear; said second gear train includes a second drive gear on the drive shaft, a second driven gear engageable with the second drive gear, an intermediate gear rotatably connected with the second driven gear, said rotary driven element connected with the tube being an output gear engaged with said intermediate gear. 
     
     
       10. The tool set forth in claim 9 wherein the second driven gear and intermediate gear are on a counter shaft and wherein said first drive gear and second driven gear are shiftable axially on their related shafts.